I have a wedding ring and an engagement ring and after the birth of DS1 37 years ago I was given an eternity ring. It was very inexpensive with teeny tiny chips of diamond (or maybe not diamond) all around, some of which have now dropped out. Two years ago I received a vintage triple ruby ring for our 40th anniversary. It was from eBay and cost less than £100. None of them are very valuable but they all have a special meaning for us.
I didn't realise how trendy I was by having a 'motherhood' ring all those years ago, though it wasn't a celebrity price.